package com.hmdp.utils;

import cn.hutool.core.lang.UUID;
import org.springframework.core.io.ClassPathResource;
import org.springframework.data.redis.core.StringRedisTemplate;
import org.springframework.data.redis.core.script.DefaultRedisScript;

import java.util.Collections;
import java.util.concurrent.TimeUnit;

public class SimpleRedisLock implements ILock {

    private StringRedisTemplate stringRedisTemplate;

    private static final String KEY_PREFIX = "lock:";

    //生成简单（32位）的UUID
    private static final String ID_PREFIX = UUID.randomUUID().toString(true) + "";

    private String name;

    private static final DefaultRedisScript<Long> UNLOCK_SCRIPT;

    static {
        UNLOCK_SCRIPT =  new DefaultRedisScript<>();
        UNLOCK_SCRIPT.setLocation(new ClassPathResource("redisUnlock.lua"));
        UNLOCK_SCRIPT.setResultType(Long.class);
    }

    public SimpleRedisLock(StringRedisTemplate stringRedisTemplate, String name) {
        this.stringRedisTemplate = stringRedisTemplate;
        this.name = name;
    }

    @Override
    public boolean tryLock(Long timeoutSec) {
        String threadId = ID_PREFIX + Thread.currentThread().getId();
        Boolean success = stringRedisTemplate.opsForValue().setIfAbsent(KEY_PREFIX + name, threadId, timeoutSec, TimeUnit.SECONDS);
        return Boolean.TRUE.equals(success);
    }

    @Override
    public void unLock() {
        // 拿锁比锁删锁的原子性动作
        stringRedisTemplate.execute(
                UNLOCK_SCRIPT,
                Collections.singletonList(KEY_PREFIX+name),
                ID_PREFIX + Thread.currentThread().getId());
    }

//    @Override
//    public void unLock() {
//        // 获取线程标示
//        String threadId = ID_PREFIX + Thread.currentThread().getId();
//        // 获取锁中的标示
//        String id = stringRedisTemplate.opsForValue().get(KEY_PREFIX + name);
//        // 判断标示是否一致
//        if(threadId.equals(id))
//            // 通过del删除锁
//            stringRedisTemplate.delete(KEY_PREFIX + name);
//    }
}
